This invention relates to a circulator known in microwave communication and the like.
As will later be described with reference to a few of several figures of the accompanying drawing, a circulator comprises a pair of conductors and at least one ferrimagnetic piece. A conventional circulator has been defective in that it has objectionable insertion loss, return loss, and like characteristics. The defects result mainly from the fact that the conductors are not brought into sufficient electric contact with the ferrimagnetic piece or pieces even though machined with a high mechanical precision in consideration of the dimensions of the ferrimagnetic piece or pieces.
In "The Bell System Technical Journal", Vol. 50, No. 7 (September 1971), pp. 2175-2194, N. R. Dietrich proposed a circulator wherein one of the conductors comprises a threaded conductive plug as an integral part thereof at the position of a ferrimagnetic piece. The plug is initially adjusted to be brought into electric contact with the ferrimagnetic piece. The proposed circulator is, however, complicated in structure and is expensive. It is troublesome to carry out the initial adjustment. In additions, it is not certain whether the characteristics are kept in good order even though the circulator is subjected to various ambient conditions.